Henry Cavendish: His Discoveries Helped Future Scientists Understand Space Contributions of Henry Cavendish to Our Understanding of Space written by: Daniel P. McGoldrick•edited by: RC Davison •updated: 5/19/2011 When Henry Cavendish died in 1810, the first trains running on rail lines were barely in existence yet the work and findings of this British physicist and chemist became integral to the understanding and exploration of space two centuries later. He literally weighed our way into history. slide 1 of 3 Truly a Man of Science Henry Cavendish was a renowned chemist and physicist who lived from 1731 to 1810, long before humans believed they could fly in our own atmosphere, let alone space. Yet his keen scientific mind made discoveries about our own planet that essentially paved the way for humans to first understand, and then explore outer space. The irony in that lies in the fact that Mr. Cavendish never married, and barely interacted with anyone, so he might as well have lived his life in a tiny capsule that housed his laboratory in space.

But that same reclusive personality enabled him to attack problems and mysteries in science like no one else. He dedicated his entire life to science and thanks to a large inheritance, he was able to study and conduct complex experiments in astronomy, chemistry, optics, electricity, geology, physics, and pure mathematics. This extremely shy and humble man made astounding contributions to the scientific community which still hold sway today. slide 2 of 3 How Did Henry Cavendish Discover Hydrogen? He is perhaps most known for first discovering and then describing the properties of hydrogen as an integral element in water, which we all of course know today as H2O. His keenly scientific mind led him to explore the relationship between zinc or iron, and water. It was known at the time that when either zinc or iron was dropped into water, a gas was produced. Cavendish dubbed this gas "inflammable air" and determined its properties and distinguished it from ordinary air. This "inflammable air" is actually hydrogen, and by combining it with oxygen in his experiments, he found out how water was formed.

As was usually the case in that era of science, another scientist tried to take credit saying he discovered it first, but when Cavendish's notebooks were finally published in the mid-nineteenth century, he was fully credited for the find (after his death). A History of Hot Air and Gas Balloons will give you an intriguing look into the practical applications of some of his work in chemistry. So what does this discovery have to do with outer space? Cavendish’s tenacity in probing, testing, and pushing the bounds of human knowledge until he broke through to a deeper level of understanding was exactly the kind of spirit and drive that it took to unlock the secrets of space. We know today that there is an extraordinary amount of Henry’s hydrogen throughout our Universe. From the beginning, NASA has utilized the distinctive properties of hydrogen for its missions, making liquid hydrogen the fuel of choice for propelling people and machinery into space. The element Cavendish discovered and closely recorded the properties of, through clever experimentation, has the lowest molecular weight of any known substance and it burns at 5,500°F. If you've ever seen footage of a NASA lift off than you know how intense that heat is.

You wouldn’t be wrong to say that there was a little bit of Henry Cavendish behind everything we sent to space. Image courtesy of Wikimedia Commons slide 3 of 3 Important Work in Understanding the Behavior of Gravity and the Density of the Earth Even today, scientists have not been able to come up with one universal theory regarding the mechanisms of the force and nature of gravity throughout the Universe. However, beginning with Newton in the seventeenth century, the behavior of objects affected by gravity has been thoroughly described and understood. Newton’s Law of Universal Gravitation essentially stated that objects in the Universe are attracted to other objects in the Universe according to a mathematical relationship between force, mass, and distance. But it was Cavendish that ingeniously confirmed this theory a century later with an experiment he designed specifically for that purpose. It was known as the Torsion Balance. There is a school of thought within the scientific community who believe it was Cavendish who conducted the first modern physics experiment because of his meticulous attention to every facet of his experimental process, including the errors. His scientific contraption led him to determining the mass and density of the Earth with simple calculations since Newton's formula was already established.

You can read about the exact formulas in Understanding the Surface Gravity of the Planets . Cavendish became famous for this work, which he published under the title “Measuring the Mass of Earth." The precision and meticulously measured nature of his experimental process became a model for all other scientists to follow. Think about how staggering that finding is, one scientist, one individual among all the billions of people who ever walked on planet Earth, was able to determine the mass of the entire planet thanks to his firm understanding of earlier scientific discoveries. Future scientists used this information to help them understand how the planets orbit around the Sun and interact with each other. This knowledge also contributed to figuring out what it would take for a rocket to escape the gravity of the Earth and negotiating the significantly lower gravitational forces of the Moon in order to land (and come back, thanks to a quick burst of the only engine they had on the lunar module). So, just like Cavendish built upon the work of the scientists who came before him, future scientists built upon his discoveries about gravity to help us navigate the vast space in our tiny neighborhood in the Universe.

Images courtesy of Wikimedia Commons Sources Hydrogen»historical information [WebElements Periodic Table] Hydrogen: historical information Hydrogen: historical information Hydrogen was discovered by Henry Cavendish at 1766 in London, England. Origin of name : from the Greek words "hydro" and "genes" meaning "water" and "generator" Robert Boyle (1627-1691; English chemist and physicist) published a paper ("New experiments touching the relation betwixt flame and air") in 1671 in which he described the reaction between iron filings and dilute acids which results in the evolution of gaseous hydrogen ("inflammable solution of Mars" [iron]). However it was only much later that it was recognized as an element by Henry Cavendish (1731-1810; an English chemist and physicist who also independently discovered nitrogen) in 1766 when he collected it over mercury and described it as "inflammable air from metals". Cavendish described accurately hydrogen's properties but thought erroneously that the gas originated from the metal rather than from the acid. Hydrogen was named by Lavoisier.

Deuterium gas (2H2, often written D2), made up from deuterium, a heavy isotope of hydrogen, was discovered in 1931 by Harold Urey, a professor of chemistry at Chicago and California (both USA). Sometime prior to the autumn of 1803, the Englishman John Dalton was able to explain the results of some of his studies by assuming that matter is composed of atoms and that all samples of any given compound consist of the same combination of these atoms. Dalton also noted that in series of compounds, the ratios of the masses of the second element that combine with a given weight of the first element can be reduced to small whole numbers (the law of multiple proportions). This was further evidence for atoms. Dalton's theory of atoms was published by Thomas Thomson in the 3rd edition of his System of Chemistry in 1807 and in a paper about strontium oxalates published in the Philosophical Transactions. Dalton published these ideas himself in the following year in the New System of Chemical Philosophy. The symbol used by Dalton for hydrogen is shown below.

[See History of Chemistry, Sir Edward Thorpe, volume 1, Watts & Co, London, 1914.] In 1839 a British scientist Sir William Robert Grove carried out experiments on electrolysis. He used electricity to split water into hydrogen and oxygen. He then argued one should be able to reverse the electrolysis and so generate electricity from the reaction of oxygen with hydrogen. He enclosed platinum strips in separate sealed bottles, one containing hydrogen and one oxygen. When the containers were immersed in dilute sulphuric acid a current indeed flowed between the two electrodes and water was formed in the gas bottles. He linked several of these devices in series to increase the voltage produced in a gas battery. Later the term fuel cell was used by the chemists Ludwig Mond and Charles Langer. In 1932 Dr Francis Thomas Bacon, an engineer at Cambridge University in the UK, worked further on designs of Mond and Langer. He replaced the platinum electrodes with less expensive nickel gauze and substituted the sulphuric acid electrolyte for alkaline potassium hydroxide (less corrosive to the electrodes). This was in essence the first alkaline fuel cell (AFC) and was called the Bacon Cell.

It took Bacon another 27 years to demonstrate a machine capable of producing 5 kW of power, enough to power a welding machine. At about the same time the first fuel cell powered vehicle was demonstrated. Much later fuel cells were by NASA in the 1960s for the Apollo space missions. Fuel cells have been used for more than 100 missions in NASA spacecraft. Fuel cells are also used in submarines. The lifting agent for the ill fated Hindenberg ballooon was hydrogen rather than the safer helium. The image below is the scene probably in a way you have not seen it before. This is a "ray-traced" image reproduced with the permission of Johannes Ewers , the artist, who won first place with this image in the March/April 1999 Internet Raytracing Competition . For details of ray-tracing you can't beat the POV-Ray site.

WebElements chemistry shop You can buy periodic table posters, mugs, T-shirts, periodic table fridge magnets, games, molecular models, and more at the WebElements periodic table shop Henry Cavendish - Chemistry Encyclopedia - water, gas, name, mass Henry Cavendish - Chemistry Encyclopedia 1731–1810 English chemist and physicist Henry Cavendish, who discovered hydrogen. Henry Cavendish, born in Nice, France to an aristocratic English family, was an avid and excellent experimenter. At the age of forty, he inherited an immense fortune that afforded him the luxury of pursuing his scientific interests (he was described by some as the "richest of all the learned and the most learned of all the rich"). He was an extraordinarily odd man, whose extreme shyness rendered him a virtual recluse. Despite this, he is remembered as a great, albeit humble, man who devoted his life to science. Cavendish explored all areas of science, including astronomy, optics, electricity, geology, and pure mathematics. Among his accomplishments are the first calculation of Earth's mass (his results were just 10% off modern measurements) and the introduction of the concept of voltage .

His principal interest nevertheless was experimental chemistry. His most famous contribution to science was the discovery and description of the properties of hydrogen and its status as a constituent element in water. Cavendish, like many before him, noticed that a gas was produced when zinc or iron was dropped into an acid. He called this gas "inflammable air" (known today as hydrogen). Using his exacting experimental skills, Cavendish was the first to distinguish this inflammable air from ordinary air and to investigate its specific properties. He presented a paper detailing his findings in 1766. The importance of inflammable air became clear about fifteen years after Cavendish presented his paper. Joseph Priestley (1733–1804) was also interested in gases, and in 1781 told Cavendish of the results of some of his own experiments. When Priestley used an electrostatic machine to spark ordinary air with inflammable air, he noticed that water was formed. Cavendish repeated this experiment, as well as others like it, but using oxygen (or, as he called it, "dephlogisticated air") in place of ordinary air.

Cavendish's results were the same as Priestley's, but he did not publish or present his findings. Sometime before 1783, however, Cavendish did advise Priestley of his results. Priestley told Charles Blagden, secretary of the Royal Society in London, and Blagden in turn informed Antoine Lavoisier (1743–1794) in France. Cavendish did eventually publish his findings on the formation of water in 1784. But Lavoisier claimed that he had discovered how water was formed—in fact, it was Lavoisier who coined the name "hydrogen," which means "water former." It was not until the mid-nineteenth century, when Cavendish's notebooks were published, that he was given sole credit for discovering that water is composed of inflammable air and dephlogisticated air, or hydrogen and oxygen. As may be seen in his collaborative work with Priestley in the investigation of the composition of water, Cavendish did not allow his natural shyness to impede his work.

The relationship between him and Priestley demonstrates not only Cavendish's devotion to science, but the general cooperative nature of scientific investigation. By sharing the results of their separate experiments, these two great scientists were able to discover the composition of water. For all of his scientific genius, Cavendish was a pronounced eccentric. He rarely left his house except for weekly meetings of the Royal Society, and even there, despite being one of the most famous scientists of his time, he was known to linger outside the meeting room and enter only when he thought no one would notice. He could barely tolerate the company of women; if any of his female servants happened to cross his path, she was likely to be fired. Though enormously wealthy, he was reputed to own but one suit, and an old-fashioned one at that. Cavendish lived a lonely and humble life, committed to the cultivation of science. To him, science was measurement, and he showed himself to be one of the most respected experimentalists of the time. His death was as lonely as his life; when he sensed that the end was near, he instructed his servant to leave the room and not come back until a certain time. When the servant returned, he found that Cavendish had died.

SEE ALSO The Element H2O The element H2O It was the chemist Henry Cavendish (1731 – 1810), who discovered the composition of water, when he experimented with hydrogen and oxygen and mixed these elements together to create an explosion (oxyhydrogen effect). In 1811 the Italian physician Amadeo Avogadro finally found the H2O formula for water. Although water has a simple molecular structure, it nevertheless has unique physical properties. It is the only element that exists on our planet in a solid, liquid and gaseous aggregate state. It is these special properties that make water so fascinating and so important for all creatures. Water has 775 times the density of air. This fact causes the ‘buoyancy’ effect, which enables us - and most mammals - to swim. Many substances expand when they are subjected to heat and reduce their density at the same time; conversely, they increase their density when cooled down. When a liquid is cooled, the colder part sinks to the bottom. The freezing process of water is the other way round. Water reaches its maximum density at 4 degrees Celsius, which is exactly 0.999973 kg/l.

Ice weighs 0.91 kg/l – which is the reason why icebergs float. This also explains why frozen water bottles explode and why fish can survive in a frozen lake. They live at the bottom where the water is the heaviest, as the temperature there is approximately 4 degrees Celsius. Water is a very bad heat conductor. This property is of utmost importance for the global climate. Water can actually store a lot of heat, which it then releases again during the cold season. In the warm season, however, it prevents excessive heating. In this way water moderates the differences in temperature. If one cubic centimetre of water evaporates (at approx. 100 degrees Celsius), its volume expands to 1243 cubic centimetres (vapour pressure) - a process that formed the basis of the construction of the steam engine; this machine eventually gave rise to the Industrial Revolution. The physical and chemical properties of water make it a universal solvent and means of transport, which is integrated into all cycles of nature, both micro- and macroscopic.

Without water, for example, there would be no circulation of nitrogen or phosphorous - both essential elements in the biosphere - as there is no way for the corresponding ions to be transported. Water can dissolve salts and feed these in dissolved form to plants. Plants then use these ions as nutrients and release the water they don’t need for their nitrogen metabolism into the atmosphere. This small water cycle is as important as the large one - without it, and therefore without water, there would be no life. Chemistry for Kids: Elements - Hydrogen Hydrogen Discovered by: Henry Cavendish in 1766 Hydrogen is the first element in the periodic table. It is the simplest possible atom composed of one proton in the nucleus which is orbited by a single electron. Hydrogen is the lightest of the elements and is the most abundant element in the universe. Characteristics and Properties At standard temperature and pressure hydrogen is a colorless, odorless, and tasteless gas. Hydrogen is very flammable and burns with an invisible flame. It burns when it comes into contact with oxygen. The byproduct of a hydrogen and oxygen explosion is water or H2 O.

Hydrogen gas is made up of diatomic molecules designated as H2. Where is hydrogen found on earth? The most common place to find hydrogen on earth is in water . Each water molecule (H2 O) contains two hydrogen atoms. Hydrogen is also found in a wide range of compounds throughout the earth including hydrocarbons, acids, and hydroxides. There is very little free hydrogen in the Earth's atmosphere because it is so light that it eventually escapes into space. The only free hydrogen on earth is deep underground. Stars and Planets Hydrogen is found mostly in stars and gas giant planets. The Sun is made up of mostly hydrogen. Deep inside stars , the pressure is so high that hydrogen atoms are converted to helium atoms. This conversion is called fusion and it releases heat and energy that we see as sunlight. How is hydrogen used today? Hydrogen is a very useful element. It is used to make ammonia for fertilizers, refining metals, and methanol for making artificial material like plastics. Hydrogen is also used as a rocket fuel where liquid hydrogen is combined with liquid oxygen to produce a powerful explosion. Scientists hope that someday hydrogen can be used as a clean fuel alternative to gasoline. How was it discovered?

English scientist Henry Cavendish discovered hydrogen as an element in 1766. Cavendish ran an experiment using zinc and hydrochloric acid. He discovered hydrogen and also found that it produced water when it burned. Where did hydrogen get its name? The name hydrogen comes from the Greek words "hydro" (meaning water) and "genes" (meaning creator). It was named by French chemist Antoine Lavoisier because when it burns it "creates water". Ions and Isotopes Hydrogen can take a negative charge and be an anion called a hydride. It can also take a positive charge as a cation. Protium is the most common isotope of hydrogen. It has no neutrons and a single proton. Other common isotopes include deuterium and tritium. Interesting Facts about Hydrogen Scientists estimate that Hydrogen makes up over 90 percent of all the atoms in the universe. It is the only element that can exist without neutrons. Hydrogen becomes a liquid at very low temperature and high pressure. Under extremely high pressure it can become a liquid metal. It is thought that metallic hydrogen exists at the cores of gas giant planets like Jupiter.

Around 10 percent of the mass of the human body is hydrogen. Because it is so light, it was once used in lighter-than-air-balloons. However, it became too dangerous because of its highly flammable nature. Hydrogen gas can be produced in a lab by combining a dilute acid with a metal. More on the Elements and the Periodic Table Henry Cavendish Biography - life, history, son, information, born, time Henry Cavendish Biography London, England English physicist and chemist The English physicist and chemist Henry Cavendish determined the value of the universal constant of gravitation, made noteworthy electrical studies, and is credited with the discovery of hydrogen and the composition of water. Early years Henry Cavendish was born in Nice, France, on October 10, 1731, the oldest son of Lord Charles Cavendish and Lady Anne Grey, who died a few years after Henry was born. As a youth he attended Dr. Newcomb's Academy in Hackney, England. He entered Peterhouse, Cambridge, in 1749, but left after three years without taking a degree. Cavendish returned to London, England to live with his father.

There, Cavendish built himself a laboratory and workshop. When his father died in 1783, Cavendish moved the laboratory to Clapham Common, where he also lived. He never married and was so reserved that there is little record of his having any social life except occasional meetings with scientific friends. Contributions to chemistry During his lifetime Cavendish made notable discoveries in chemistry, mainly between 1766 and 1788, and in electricity, between 1771 and 1788. In 1798 he published a single notable paper on the density of the earth. At the time Cavendish began his chemical work, chemists were just beginning to recognize that the "airs" that were evolved in many chemical reactions were clear parts and not just modifications of ordinary air. Cavendish reported his own work in "Three Papers Containing Experiments on Factitious Air" in 1766. These papers added greatly to knowledge of the formation of "inflammable air" (hydrogen) by the action of dilute acids (acids that have been weakened) on metals.

Cavendish's other great achievement in chemistry is his measuring of the density of hydrogen. Although his figure is only half what it should be, it is astonishing that he even found the right order. Not that his equipment was crude; where the techniques of his day allowed, his equipment was capable of precise results. Cavendish also investigated the products of fermentation, a chemical reaction that splits complex organic compounds into simple substances. He showed that the gas from the fermentation of sugar is nearly the same as the "fixed air" characterized by the compound of chalk and magnesia (both are, in modern language, carbon dioxide). Another example of Cavendish's ability was "Experiments on Rathbone-Place Water"(1767), in which he set the highest possible standard of accuracy. "Experiments" is regarded as a classic of analytical chemistry (the branch of chemistry that deals with separating substances into the different chemicals Henry Cavendish. Library of Congress . they are made from). In it Cavendish also examined the phenomenon (a fact that can be observed) of the retention of "calcareous earth" (chalk, calcium carbonate) in solution (a mixture dissolved in water).

In doing so, he discovered the reversible reaction between calcium carbonate and carbon dioxide to form calcium bicarbonate, the cause of temporary hardness of water. He also found out how to soften such water by adding lime (calcium hydroxide). One of Cavendish's researches on the current problem of combustion (the process of burning) made an outstanding contribution to general theory. In 1784 Cavendish determined the composition (make up) of water, showing that it was a combination of oxygen and hydrogen. Joseph Priestley (1733–1804) had reported an experiment in which the explosion of the two gases had left moisture on the sides of a previously dry container. Cavendish studied this, prepared water in measurable amount, and got an approximate figure for its volume composition. Electrical research Cavendish published only a fraction of the experimental evidence he had available to support his theories, but his peers were convinced of the correctness of his conclusions. He was not the first to discuss an inverse-square law of electrostatic attraction (the attraction between opposite—positive and negative—electrical charges). Cavendish's idea, however, based in part on mathematical reasoning, was the most effective.

He founded the study of the properties of dielectrics (nonconducting electricity) and also distinguished clearly between the amount of electricity and what is now called potential. Cavendish had the ability to make a seemingly limited study give far-reaching results. An example is his study of the origin of the ability of some fish to give an electric shock. He made up imitation fish of leather and wood soaked in salt water, with pewter (tin) attachments representing the organs of the fish that produced the effect. By using Leyden jars (glass jars insulated with tinfoil) to charge the imitation organs, he was able to show that the results were entirely consistent with the fish's ability to produce electricity. This investigation was among the earliest in which the conductivity of aqueous (in water) solutions was studied. Cavendish began to study heat with his father, then returned to the subject in 1773–1776 with a study of the Royal Society's meteorological instruments. (The Royal Society is the world's oldest and most distinguished scientific organization.) During these studies he worked out the most important corrections to be employed in accurate thermometry (the measuring of temperature).

In 1783 he published a study of the means of determining the freezing point of mercury. In it he added a good deal to the general theory of fusion (melting together by heat) and freezing and the latent heat changes that accompany them (the amount of heat absorbed by the fused material). Cavendish's most celebrated investigation was that on the density of the earth. He took part in a program to measure the length of a seconds pendulum close to a large mountain (Schiehallion). Variations from the period on the plain would show the attraction put out by the mountain, from which the density of its substance could be figured out. Cavendish also approached the subject in a more fundamental way by determining the force of attraction of a very large, heavy lead ball for a very small, light ball. The ratio between this force and the weight of the light ball would result in the density of the earth. His results went unquestioned for nearly a century. Unpublished works Had Cavendish published all of his work, his already great influence would undoubtedly have been greater. In fact, he left in manuscript form a vast amount of work that often anticipated the work of those who followed him.

It came to light only bit by bit until the thorough study undertaken by James Maxwell (1831–1879) and by Edward Thorpe (1845–1925). In these notes is to be found such material as the detail of his experiments to examine the conductivity of metals, as well as many chemical questions such as a theory of chemical equivalents. He even had a theory of partial pressures before John Dalton (1766–1844). However, the history of science is full of instances of unpublished works that might have influenced others but in fact did not. Whatever he did not reveal, Cavendish gave other scientists enough to help them on the road to modern ideas. Nothing he did has been rejected, and for this reason he is still, in a unique way, part of modern life. For More Information Henry Cavendish, Discovery of Hydrogen - Timeline Index Timeline Index 1731 - 1810 79 years Henry Cavendish, Discovery of Hydrogen Henry Cavendish was a British scientist noted for his discovery of hydrogen or what he called "inflammable air".

He described the density of inflammable air, which formed water on combustion, in a 1766 paper "On Factitious Airs". Antoine Lavoisier later reproduced Cavendish's experiment and gave the element its name. Cavendish is also known for the Cavendish experiment, his measurement of the Earth's density, and early research into electricity. More on this Website Which Elements Were Discovered In London? | Londonist Which Elements Were Discovered In London? By Laurence Scales Last edited 20 months ago Laurence Scales Which Elements Were Discovered In London? Consider everything around you as if it was a ‘bake-off’ — the air, your elbow, a phone. The list of possible ingredients — the chemical elements — is usually reckoned to number 92. London can boast the discovery of a fifth of these, including bone-building calcium, precious palladium, and radioactive radon. Counting discoveries is tricky, but here’s our round-up of those identified in the city. Inflammable Air Hydrogen cylinders mounted on the roof of an RV1 hydrogen powered bus, which produces water as exhaust. Always make water when you can, said the Duke of Wellington.

Answering the call of nature in an intellectual sense was natural philosopher Henry Cavendish. He was not the first person to make hydrogen but, in 1766, he was the first to realise, at his rural laboratory in Clapham, that it was an element. He called it "inflammable air" but it was later given the more convenient name of hydrogen, coming from the Greek for ‘make water’ because Cavendish showed it to be a constituent of water. He had not finished with ‘airs’. Air is a mixture of gases and Cavendish puzzled over a residue of his samples that refused to react with anything. This unfinished business lingered on for a century. London Palladium A lump of palladium. Palladium is a lustrous metal, one of the four precious metals that need a hallmark. It was named after the asteroid Pallas, discovered around the same time in 1803. Palladium is chemically like platinum, a substance studied by William Hyde Wollaston at his laboratory just off Fitzroy Square. He discovered palladium in residue from his platinum experiments. Many elements have been discovered in odd residues leftover when work was supposedly finished.

Wollaston did not trumpet his discovery but put palladium on sale under the name 'new silver' at a Mr and Mrs Forster's shop at 26 Gerrard Street and offered a huge £20 prize to anyone who could assemble it from other elements in front of witnesses. No one was able to claim the prize and Wollaston unmasked himself as the discoverer of palladium in 1805. He also discovered rhodium (in a residue). Skint Boron crops up in Cockney rhyming slang and it was indeed isolated a couple of miles from Bow bells. To those born within the sound of the bells, 'boracic lint' means skint. Oddly, 'skint' (penniless) derives from 'skinned' and borax, a boron compound, has long been used to soothe the skin. Experiments involving the new-fangled electric current from a huge battery in the basement of the Royal Institution in Mayfair were conducted by Sir Humphry Davy. He isolated first metallic potassium then sodium in 1807, and in 1808 came boron, barium, calcium, strontium and magnesium.

Humphry Davy’s home-made samples of elements at the Royal Institution: green chlorine gas, calcium and magnesium metals and sodium (in oil). His assistant, Edmund Davy described the moment Sir Humphrey had his breakthrough: "When he first saw the minute globules of potassium burst through the crust of potash, and take fire as they entered the atmosphere, he could not contain his joy — he actually danced about the room in ecstatic delight." Sodium is similar and both are usually stored under oil as they react violently with water. Magnesium’s dazzling flame peps up fireworks. But boring boron must have been something of a disappointment. The Royal Institution claims the discovery of 10 elements. After various tests Davy decided chlorine was an element in 1810. But he nailed iodine in a hotel room in France. So we discount iodine. We'll come back to the other one later. Poison Thallium poisoning was a murderous modus operandi used by detective story writer Agatha Christie, devious because of the delayed onset of its effect and the symptoms which might suggest other causes. In Victorian times thallium was used as a rat poison and sometimes even used medically.

It was also an early suspect in the recent Litvinenko case. The element was discovered in 1861 by William Crookes, who had a home and laboratory at Mornington Terrace, Euston. After an observation by Wollaston of dark lines in the light spectrum obtained from the sun, followed by further discoveries that certain colours were characteristic of certain elements, Crookes observed a brilliant green colour in a flame and went on to show that he had a new element, which he named after the Greek for bud, a nod to its green flame. Sunshine on Kilburn Norman Lockyer. Photograph by Walery. Helium had the distinction of being discovered in the sun before any was found on earth, also given away by its colour signature. Norman Lockyer, a civil servant at the War Office, deduced the existence of a new element in 1868 with the aid of his telescope in the modest and smoggy environs of his home in Kilburn. You Wait for Decades, Then Several Turn Up at Once Science sometimes advances by picking at niggling details. Lord Rayleigh, at the Royal Institution again, was puzzled by Cavendish’s tiny residue of air when everything known had been extracted.

It turned out to be argon, and was described in 1894. Argon is one of the ‘inert’ gases. Another, helium, was finally caught seeping from rocks by William Ramsay at University College in 1895 and he went hunting for others. Xenon, krypton and neon came in 1898 when he wondered if his argon sample was pure, and found that it wasn’t. Radon was first collected in 1910. It is a natural but invisible hazard in mines and granite buildings. Rayleigh and William Ramsay picked up Nobel Prizes in 1904 for finding the inert gases. These gases are surprisingly useful despite being inert, and find application in refrigeration , welding, diving, lighting , lasers and medical imaging . Last Updated 20 April 2015 When Was The Element Discovered? Timeline | Preceden Silver Discovered 3400 bc Silver was written about in 900BC in India, though we do not know who discovered or when Silver. Silver has been in use as far back as 3400BC in Egyptian objects. Silver has the ability to halt bacteria and fungi growth.

This is why Silver can be found in wound dressings. (Due to the fact that there is no date of discovery, I used the date since the element was in use.) Mercury Discovered 1500 bc It is unsure when or who discovered Mercury, but it was in use since 1500BC by the Chinese, Egyptians and Hindus. Chinese Emperors once used Mercury in medicine to prolongate their lives but we now know that Mercury probably shortened the Emperor's life due to Mercury's toxins that may severely harm people. (Due to the fact that there is no date of discovery, I used the date since the element was in use.) Arsenic Discovered 800 ad Arsenic is said to be discovered as a unique element by Geber (an alchemist) in 800BC. Geber recorded how to prepare Arsenic in "Liber Fornacum". Many accredit this discovery to Albertus Magnus who found Arsenic in 1250BC. Arsenic is utilised in modern animal feeds to stimulate growth and prevent disease. Phosphorus Discovered 1669 ad Phosphorus was discovered in 1 by German alchemist, Henning Brand.

Brand stumbled upon Phosphorus when trying the create 'the Philosopher's Stone'. Whilst experimenting with urine Brand managed to separate a white glowing material which happened to be Phosphorus. Phosphorus is part of DNA, RNA, and ATP, this means every living cell requires and has Phosphorus. Cobalt Discovered 1735 ad A Swedish chemist by the name of Georg Brandt, was the first person to successfully isolate Cobalt, which was done in 1735 ad. Cobalt was in use since 400 bc by the Egyptians in sculptures. Cobalt is known for the magnificent blue colour it stains glass, ceramic and glazes with. Cobalt is able to withstand enormous temperatures, it becomes solid at room temperature and doesn't melt til 1495 degrees Celsius. Hydrogen Discovered 1766 ad Paracelsus (1500's ad) and Robert Boyle (1671 ad) had both discovered Hydrogen but hadn't followed up on their discoveries. Therefore Henry Cavendish is accredited for the discovery of Hydrogen. Henry also proved that water wasn't made up of one element, by burning the Hydrogen.

Hydrogen can be found in the sun and all other stars, in fact Jupiter the planet is mostly consistent of Hydrogen. It is thought that Hydrogen is the most abundant element in universe. Chlorine Discovered 1774 ad Carl Wilhelm Scheele a Swedish chemist was the first person to isolate Chlorine gas and he continued to study Chlorine. Around 900 ad a Persian alchemist created a form of Chlorine called Hydrochloric acid, which combined with nitric was used to dissolve gold around 1200 ad. Despite its prior discovery Chlorine was regarded as a unique element until 1810 by Sir Humphry Davy. Tungsten Discoverd 1783 ad Discovered by two Swedish brothers who were both chemist, Juan Jose and Fausto Elhuyar in 1783. It was discovered when the brothers were analyzing samples of the mineral wolframite. They succeeded in isolating the tungsten from wolframite by reducing the acid to charcoal. Tungsten to this day is extract using the same method the two brothers who discovered it used, from wolframite and scheelite.

Uranium Discovered 1789 ad Martin Heinrich Klaproth isolated the Uranium oxide in 1789 and he had mistaken it for a new element. Only in 1841 ad had the metal Uranium get isolated, which was done by Eugene-Melchior Peligot. Uranium oxide used to be used as yellow pigment in ceramic glazes in early 79 ad. Calcium Discovered 1808 ad Calcium discovered by Sir Humphry Davy a British chemist in 1808 through electrolysis (direct electric current to cause a reaction that otherwise wouldn't occur) of lime and mercuric oxide. Calcium is always found as a part of several minerals, and is the fifth most abundant element in our Earth's crust, making it essential to life. Boron Discovered 1808 ad Sir Humphry Davy, Joseph Louis Gay-Lussac and Louis Jacques Thenard reacted boric acid with potassium and ended up isolating a new element, Boron which Davy originally named Boracium. Boron acid is sometimes found in volcanic spring waters, and isn't toxic to mammals.

Bromine Discovered 1825 ad Bromine was discovered when Carl Jacob isolated Bromine from spring waters in his hometown. He saturated a solution of the mineral using chlorine and used an ether for the extraction of the Bromine. Others say that Antoine Ballard discovered Bromine in 1826 ad since Jacob published his findings a long time after he found them. Ballard extracted Bromine from seaweed, by reacting seaweed ash with chlorine. Aluminum Discovered 1825 ad Hans Christian Orsted first isolated and produced Aluminum as a metal in 1825 by reacting Aluminum Chloride with Potassium Amalgam. Before Orsted discovered Aluminum metal, ancient Greeks and Romans used Aluminum salts to dress wounds and was considered to be more precious than Gold! Aluminum is extremely reactive resulting in Aluminum never being found uncombined in nature. Helium Discovered 1895 ad Helium was sited by a French astronomer Pierre Janssen while observing the solar eclipse in 1868 ad. Helium wasn't isolated til 1895 by Sir William Ramsay.

Ramsay treated mineral cleveite with mineral acids, when he analysed the mixture, Ramsay discovered a yellow line in the emission spectrum (a band of colours).This yellow line was Helium. Helium is lighter than air and is the second most abundant element in the universe. Radium Discovered 1898 ad Radium was discovered by Marie Sklodowska Curie a Polish chemist and French chemist Pierre Curie in 1898. Marie Curie discovered Radium from a pitchblende. Marie extracted the Uranium from the Pitchblende but then noticed the Pitchblende still contained some kind of strong radioactive element. Maria Curie refined several tons of pitchblende to extract only tiny amounts of radium and polonium ( another radioactive element Curie discovered). Radium is around one million times more radioactive the Uranium. Radium is so radioactive that Curie's notebooks are far too radioactive to be handled safetly to this day. Hafnium Discovered 1923 ad X-ray spectroscopy was used to discover Hafnium in 1923 by Danish chemist Dirk Coster and Hungarian chemist Charles de Hevesy.

X-ray spectroscopy was used to study the arrangement of the electrons on the outer shell of zirconium. The task of isolating the Hafnium is a hard one, since Hafnium is in every ore of zirconium. Hafnium is used in the control rods (regulate heat to insure center doesn't melt down) of nuclear reactors since it is a good absorber of neutrons.. Rhenium Discovered 1925 Rhenium was discovered by German chemists Ida Tacke-Noddack, Walter Noddack, and Otto Carl Berg. This group detected Rhenium spectroscopically in platinum ores and in the minerals columbite, gadolinite and molybdenite. Nowadays Rhenium isolated as a byproduct of refining molybdenum and copper. Einsteinium Discovered 1952 ad Einsteinium was discovered by a group of scientists lead by Albert Ghiorso as they were studying the radioactive debris from the first detonated hydrogen bomb. Einsteinium was discovered by combining 15 neutrons with Uranium.

Einsteinium requires a long process and can only be made in small quantities so Einsteinium is only used for scientific purposes.

Question: Henry Cavendish discovered which element?
Answer: HYDROGEN